The invention relates to a vacuum valve comprising:    a wall with a valve opening that is surrounded by a valve seat,    at least one valve plate arranged in a vacuum region of the vacuum valve,    wherein this valve plate can be moved from an open position in which it opens up the valve opening in a longitudinal direction into an intermediate position in which it covers the valve opening but is lifted from the valve seat and from its intermediate position in a transverse direction at a right angle to the longitudinal direction into a closed position in which it is pressed onto the valve seat and closes the valve opening,    at least one valve rod that carries the valve plate and is led out from the vacuum region of the vacuum valve and can be displaced relative to the wall in the longitudinal direction lying parallel to the longitudinal axis of the valve rod and also can be displaced parallel to the wall in the transverse direction,    a longitudinal drive device is arranged outside of the vacuum region of the vacuum valve by which the valve rod can be displaced in the longitudinal direction for adjusting the valve plate between its open position and its intermediate position, and    a transverse drive device is arranged outside of the vacuum region of the vacuum valve and by which the valve rod can be displaced in the transverse direction for adjusting the valve plate between its intermediate position and its closed position.
Such vacuum valves are also designated as L-valves that are known in different constructions. In a common construction not according to the class, the valve rod is supported so that it can pivot about an axis at a right angle to the longitudinal direction and at a right angle to the transverse direction, in order to allow the adjustment of the valve plate from its intermediate position into its closed position and back again. Such a construction follows, for example, from U.S. Pat. No. 6,431,518 B1. The cylinder of the piston-cylinder unit forming the longitudinal drive can be pivoted together with the valve rod and another piston-cylinder unit is used for pivoting the valve rod and the cylinder. A similar device is also known from U.S. Pat. No. 6,416,037 B1. A common construction also provides that the tilting of the valve rod is performed by means of a connecting-link guide by the same piston-cylinder unit generating the longitudinal drive, as emerges, for example, from U.S. Pat. No. 6,966,538 B2, U.S. Pat. No. 5,641,149 A, U.S. Pat. No. 6,237,892 B1, and U.S. Pat. No. 6,619,618 B2.
One disadvantage of these known L-valves in which the adjustment of the valve plate in the transverse direction is performed by a tilting of the valve rod consists in that the adjustment of the valve plate is not performed exactly and in parallel, but instead only approximately in the transverse direction, which leads to elevated loading of the seal that seals the valve plate relative to the valve seat.
Furthermore, so-called J-valves are also known in which the striking of the valve plate on the valve seat is performed at a very oblique angle to the transverse direction.
Furthermore, L-valves have become known in which the adjustment of the valve plate from its intermediate position into its closed position is performed by a straight-line displacement in the transverse direction. For example, from U.S. 2007/0272888 A1 of the applicant, a vacuum valve emerges in which the valve plate can be displaced in the transverse direction relative to a carrier unit by means of piston-cylinder units. The carrier unit is arranged on valve rods that can be displaced in the longitudinal direction by means of additional piston-cylinder units. In addition to a construction as a vacuum valve, this device could also be constructed as gates in which the valve plate closes an opening in a wall of a vacuum chamber from the outside and here can lie outside of the vacuum region. A similar vacuum valve with piston-cylinder units for the longitudinal displacement of valve rods that carry a carrier unit and for the transverse displacement of a valve plate relative to the carrier unit is known from U.S. Pat. No. 6,899,316 A.
From U.S. 2008/0017822 A1, an L-valve is known in which the valve plate is attached to a valve rod that is guided so that it can be displaced in the longitudinal direction and can be adjusted in the longitudinal direction by means of a piston-cylinder unit. Through the use of a guide device that is formed in one embodiment by a linear guide, this piston-cylinder unit is guided so that it can be displaced in the transverse direction, wherein the piston rod can also be displaced in the transverse direction relative to the wall having the valve opening. For adjusting the valve plate from its intermediate position into its closed position, a piston-cylinder unit integrated in the valve plate is used. In another embodiment, the transverse drive device is formed by a piston-cylinder unit arranged outside of the vacuum region, with this piston-cylinder unit acting on the cylinder of the piston-cylinder unit of the longitudinal drive device. It is constructed so that such a construction is suitable, in particular, for applications in which the valve plate is loaded only by a differential pressure that presses the valve plate onto the valve seat. In this case, a closing force pressing the valve plate onto the valve seat does not have to be applied. The transmission of a larger closing force would be problematic with the transverse guide emerging from this publication.